Programmed cell death, or apoptosis, is one of the body’s ways of getting rid of old, faulty or infected cells.

This process is often blocked, which is why some drugs do not work, allowing tumour cells to keep dividing and spread.

The treatment works by using tiny iron nanoparticles attached to antibodies which bind to receptor molecules on tumour cells.

When the magnetic field is turned on, the molecules cluster together, triggering the “death signal”.

This new process raises the hope of new targeted treatments that could kill tumour cells resistant to programmed cell death.

Scientists at Yonsei University in Seoul, South Korea, found in laboratory tests that over half of bowel cancer cells exposed to the nanoparticles and put between two magnets were destroyed by magnetic activation. Untreated cells were unaffected.

“Research like this shows how ingenious scientists are in the quest to beat cancer,” said Henry Scowcroft, at Cancer Research UK.